Uplink control channel resource allocation

ABSTRACT

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may determine a resource allocation, from a resource set, for a response message using a resource allocation selection procedure. In some aspects, the user equipment may transmit the response message using the resource allocation and based at least in part on determining the resource allocation. In some aspects, the user equipment may determine, using an implicit resource mapping procedure and before a radio resource control connection establishment, a resource allocation for a redundancy scheme response message based at least in part on a remaining minimum system information (RMSI) value. Numerous other aspects are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS UNDER 35 U.S.C. § 119

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/616,932, filed on Jan. 12, 2018, entitled “TECHNIQUES ANDAPPARATUSES FOR BANDWIDTH PART SWITCH MANAGEMENT,” which is herebyexpressly incorporated by reference herein.

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/617,565, filed on Jan. 15, 2018, entitled “TECHNIQUES ANDAPPARATUSES FOR BANDWIDTH PART SWITCH MANAGEMENT,” which is herebyexpressly incorporated by reference herein.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wirelesscommunication, and more particularly to techniques and apparatuses foruplink control channel resource allocation.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, and/or the like). Examples of such multiple-accesstechnologies include code division multiple access (CDMA) systems, timedivision multiple access (TDMA) systems, frequency-division multipleaccess (FDMA) systems, orthogonal frequency-division multiple access(OFDMA) systems, single-carrier frequency-division multiple access(SC-FDMA) systems, time division synchronous code division multipleaccess (TD-SCDMA) systems, and Long Term Evolution (LTE).LTE/LTE-Advanced is a set of enhancements to the Universal MobileTelecommunications System (UMTS) mobile standard promulgated by theThird Generation Partnership Project (3GPP).

A wireless communication network may include a number of base stations(BSs) that can support communication for a number of user equipment(UEs). A user equipment (UE) may communicate with a base station (BS)via the downlink and uplink. The downlink (or forward link) refers tothe communication link from the BS to the UE, and the uplink (or reverselink) refers to the communication link from the UE to the BS. As will bedescribed in more detail herein, a BS may be referred to as a Node B, agNB, an access point (AP), a radio head, a transmit receive point (TRP),a new radio (NR) BS, a 5G Node B, and/or the like.

The above multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent user equipment to communicate on a municipal, national,regional, and even global level. New radio (NR), which may also bereferred to as 5G, is a set of enhancements to the LTE mobile standardpromulgated by the Third Generation Partnership Project (3GPP). NR isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingorthogonal frequency division multiplexing (OFDM) with a cyclic prefix(CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g.,also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) onthe uplink (UL), as well as supporting beamforming, multiple-inputmultiple-output (MIMO) antenna technology, and carrier aggregation.However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in LTE and NRtechnologies. Preferably, these improvements should be applicable toother multiple access technologies and the telecommunication standardsthat employ these technologies.

SUMMARY

In some aspects, a method of wireless communication may includedetermining a resource allocation, from a resource set, for a responsemessage using a resource allocation selection procedure based at leastin part on at least one of a downlink assignment characteristic, adownlink assignment index (DAI) value, a resource set characteristic forthe resource set, a quantity of acknowledgement bits in anacknowledgement message, or a response message resource indicator value.The resource allocation selection procedure may be an implicit resourcemapping procedure combined with explicit signaling. The method mayinclude transmitting the response message using the resource allocationand based at least in part on determining the resource allocation.

In some aspects, a user equipment for wireless communication may includememory and one or more processors coupled to the memory. The memory andthe one or more processors may be configured to determine a resourceallocation, from a resource set, for a response message using a resourceallocation selection procedure based at least in part on at least one ofa downlink assignment characteristic, a DAI value, a resource setcharacteristic for the resource set, a quantity of acknowledgement bitsin an acknowledgement message, or a response message resource indicatorvalue. The resource allocation selection procedure may be an implicitresource mapping procedure combined with explicit signaling. The memoryand the one or more processors may be configured to transmit theresponse message using the resource allocation and based at least inpart on determining the resource allocation.

In some aspects, a non-transitory computer-readable medium may store oneor more instructions for wireless communication. The one or moreinstructions, when executed by one or more processors of a userequipment, may cause the one or more processors to determine a resourceallocation, from a resource set, for a response message using a resourceallocation selection procedure based at least in part on at least one ofa downlink assignment characteristic, a DAI value, a resource setcharacteristic for the resource set, a quantity of acknowledgement bitsin an acknowledgement message, or a response message resource indicatorvalue. The resource allocation selection procedure may be an implicitresource mapping procedure combined with explicit signaling. The one ormore instructions, when executed by the one or more processors of theuser equipment, may cause the one or more processors to transmit theresponse message using the resource allocation and based at least inpart on determining the resource allocation.

In some aspects, an apparatus for wireless communication may includemeans for determining a resource allocation, from a resource set, for aresponse message using a resource allocation selection procedure basedat least in part on at least one of a downlink assignmentcharacteristic, a DAI value, a resource set characteristic for theresource set, a quantity of acknowledgement bits in an acknowledgementmessage, or a response message resource indicator value. The resourceallocation selection procedure may be an implicit resource mappingprocedure combined with explicit signaling. The apparatus may includemeans for transmitting the response message using the resourceallocation and based at least in part on determining the resourceallocation.

In some aspects, a method of wireless communication may includedetermining, using an implicit resource mapping procedure and before aradio resource control connection establishment, a resource allocationfor a redundancy scheme response message based at least in part on aremaining minimum system information (RMSI) value. The method mayinclude transmitting the redundancy scheme response message using theresource allocation based at least in part on determining the resourceallocation.

In some aspects, a user equipment for wireless communication may includememory and one or more processors coupled to the memory. The memory andthe one or more processors may be configured to determine, using animplicit resource mapping procedure and before a radio resource controlconnection establishment, a resource allocation for a redundancy schemeresponse message based at least in part on an RMSI value. The memory andthe one or more processors may be configured to transmit the redundancyscheme response message using the resource allocation based at least inpart on determining the resource allocation.

In some aspects, a non-transitory computer-readable medium may store oneor more instructions for wireless communication. The one or moreinstructions, when executed by one or more processors of a userequipment, may cause the one or more processors to determine, using animplicit resource mapping procedure and before a radio resource controlconnection establishment, a resource allocation for a redundancy schemeresponse message based at least in part on a RMSI value. The one or moreinstructions, when executed by the one or more processors of the userequipment, may cause the one or more processors to transmit theredundancy scheme response message using the resource allocation basedat least in part on determining the resource allocation.

In some aspects, an apparatus for wireless communication may includemeans for determining, using an implicit resource mapping procedure andbefore a radio resource control connection establishment, a resourceallocation for a redundancy scheme response message based at least inpart on a RMSI value. The apparatus may include means for transmittingthe redundancy scheme response message using the resource allocationbased at least in part on determining the resource allocation.

Aspects generally include a method, apparatus, device, computer programproduct, non-transitory computer-readable medium, user equipment,wireless communication device, base station, access point, andprocessing system as substantially described herein with reference toand as illustrated by the accompanying drawings and specification.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can beunderstood in detail, a more particular description, briefly summarizedabove, may be had by reference to aspects, some of which are illustratedin the appended drawings. It is to be noted, however, that the appendeddrawings illustrate only certain typical aspects of this disclosure andare therefore not to be considered limiting of its scope, for thedescription may admit to other equally effective aspects. The samereference numbers in different drawings may identify the same or similarelements.

FIG. 1 is a block diagram conceptually illustrating an example of awireless communication network, in accordance with various aspects ofthe present disclosure.

FIG. 2 is a block diagram conceptually illustrating an example of a basestation in communication with a user equipment (UE) in a wirelesscommunication network, in accordance with various aspects of the presentdisclosure.

FIG. 3A is a block diagram conceptually illustrating an example of aframe structure in a wireless communication network, in accordance withvarious aspects of the present disclosure.

FIG. 3B is a block diagram conceptually illustrating an examplesynchronization communication hierarchy in a wireless communicationnetwork, in accordance with various aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating an example subframeformat with a normal cyclic prefix, in accordance with various aspectsof the present disclosure.

FIG. 5 illustrates an example logical architecture of a distributedradio access network (RAN), in accordance with various aspects of thepresent disclosure.

FIG. 6 illustrates an example physical architecture of a distributedRAN, in accordance with various aspects of the present disclosure.

FIG. 7 is a diagram illustrating an example of a downlink (DL)-centricsubframe, in accordance with various aspects of the present disclosure.

FIG. 8 is a diagram illustrating an example of an uplink (UL)-centricsubframe, in accordance with various aspects of the present disclosure.

FIG. 9 is a diagram illustrating an example of uplink control channelresource allocation determination, in accordance with various aspects ofthe present disclosure.

FIG. 10 is a diagram illustrating an example process performed, forexample, by a user equipment, in accordance with various aspects of thepresent disclosure.

FIG. 11 is a diagram illustrating an example process performed, forexample, by a user equipment, in accordance with various aspects of thepresent disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based at least inpart on the teachings herein one skilled in the art should appreciatethat the scope of the disclosure is intended to cover any aspect of thedisclosure disclosed herein, whether implemented independently of orcombined with any other aspect of the disclosure. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, the scope of thedisclosure is intended to cover such an apparatus or method which ispracticed using other structure, functionality, or structure andfunctionality in addition to or other than the various aspects of thedisclosure set forth herein. It should be understood that any aspect ofthe disclosure disclosed herein may be embodied by one or more elementsof a claim.

Several aspects of telecommunication systems will now be presented withreference to various apparatuses and techniques. These apparatuses andtechniques will be described in the following detailed description andillustrated in the accompanying drawings by various blocks, modules,components, circuits, steps, processes, algorithms, and/or the like(collectively referred to as “elements”). These elements may beimplemented using hardware, software, or combinations thereof. Whethersuch elements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

It should be noted that while aspects may be described herein usingterminology commonly associated with 3G and/or 4G wireless technologies,aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

FIG. 1 is a diagram illustrating a network 100 in which aspects of thepresent disclosure may be practiced. The network 100 may be an LTEnetwork or some other wireless network, such as a 5G or NR network.Wireless network 100 may include a number of BSs 110 (shown as BS 110 a,BS 110 b, BS 110 c, and BS 110 d) and other network entities. A BS is anentity that communicates with user equipment (UEs) and may also bereferred to as a base station, a NR BS, a Node B, a gNB, a 5G node B(NB), an access point, a transmit receive point (TRP), and/or the like.Each BS may provide communication coverage for a particular geographicarea. In 3GPP, the term “cell” can refer to a coverage area of a BSand/or a BS subsystem serving this coverage area, depending on thecontext in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or another type of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). ABS for a macro cell may bereferred to as a macro BS. ABS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1, a BS 110 a may be a macro BSfor a macro cell 102 a, a BS 110 b may be a pico BS for a pico cell 102b, and a BS 110 c may be a femto BS for a femto cell 102 c. A BS maysupport one or multiple (e.g., three) cells. The terms “eNB”, “basestation”, “NR BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” maybe used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of amobile BS. In some aspects, the BSs may be interconnected to one anotherand/or to one or more other BSs or network nodes (not shown) in theaccess network 100 through various types of backhaul interfaces such asa direct physical connection, a virtual network, and/or the like usingany suitable transport network.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., a BS or a UE) and send a transmission of the data to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay station 110 d may communicate with macro BS 110 a and aUE 120 d in order to facilitate communication between BS 110 a and UE120 d. A relay station may also be referred to as a relay BS, a relaybase station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/orthe like. These different types of BSs may have different transmit powerlevels, different coverage areas, and different impact on interferencein wireless network 100. For example, macro BSs may have a high transmitpower level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relayBSs may have lower transmit power levels (e.g., 0.1 to 2 Watts).

A network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, and/or the like. A UE may be a cellularphone (e.g., a smart phone), a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, medical device or equipment, biometric sensors/devices,wearable devices (smart watches, smart clothing, smart glasses, smartwrist bands, smart jewelry (e.g., smart ring, smart bracelet)), anentertainment device (e.g., a music or video device, or a satelliteradio), a vehicular component or sensor, smart meters/sensors,industrial manufacturing equipment, a global positioning system device,or any other suitable device that is configured to communicate via awireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolvedor enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEsinclude, for example, robots, drones, remote devices, sensors, meters,monitors, location tags, and/or the like, that may communicate with abase station, another device (e.g., remote device), or some otherentity. A wireless node may provide, for example, connectivity for or toa network (e.g., a wide area network such as Internet or a cellularnetwork) via a wired or wireless communication link. Some UEs may beconsidered Internet-of-Things (IoT) devices, and/or may be implementedas may be implemented as NB-IoT (narrowband internet of things) devices.Some UEs may be considered a Customer Premises Equipment (CPE). UE 120may be included inside a housing that houses components of UE 120, suchas processor components, memory components, and/or the like.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular RAT andmay operate on one or more frequencies. A RAT may also be referred to asa radio technology, an air interface, and/or the like. A frequency mayalso be referred to as a carrier, a frequency channel, and/or the like.Each frequency may support a single RAT in a given geographic area inorder to avoid interference between wireless networks of different RATs.In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE 120 a and UE 120e) may communicate directly using one or more sidelink channels (e.g.,without using a base station 110 as an intermediary to communicate withone another). For example, the UEs 120 may communicate usingpeer-to-peer (P2P) communications, device-to-device (D2D)communications, a vehicle-to-everything (V2X) protocol (e.g., which mayinclude a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure(V2I) protocol, and/or the like), a mesh network, and/or the like. Inthis case, the UE 120 may perform scheduling operations, resourceselection operations, and/or other operations described elsewhere hereinas being performed by the base station 110.

As indicated above, FIG. 1 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 1.

FIG. 2 shows a block diagram of a design 200 of base station 110 and UE120, which may be one of the base stations and one of the UEs in FIG. 1.Base station 110 may be equipped with T antennas 234 a through 234 t,and UE 120 may be equipped with R antennas 252 a through 252 r, where ingeneral T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from adata source 212 for one or more UEs, select one or more modulation andcoding schemes (MCS) for each UE based at least in part on channelquality indicators (CQIs) received from the UE, process (e.g., encodeand modulate) the data for each UE based at least in part on the MCSselected for the UE, and provide data symbols for all UEs. Transmitprocessor 220 may also process system information (e.g., for semi-staticresource partitioning information (SRPI) and/or the like) and controlinformation (e.g., CQI requests, grants, upper layer signaling, and/orthe like) and provide overhead symbols and control symbols. Transmitprocessor 220 may also generate reference symbols for reference signals(e.g., the cell-specific reference signal (CRS)) and synchronizationsignals (e.g., the primary synchronization signal (PSS) and secondarysynchronization signal (SSS)). A transmit (TX) multiple-inputmultiple-output (MIMO) processor 230 may perform spatial processing(e.g., precoding) on the data symbols, the control symbols, the overheadsymbols, and/or the reference symbols, if applicable, and may provide Toutput symbol streams to T modulators (MODs) 232 a through 232 t. Eachmodulator 232 may process a respective output symbol stream (e.g., forOFDM and/or the like) to obtain an output sample stream. Each modulator232 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal. Tdownlink signals from modulators 232 a through 232 t may be transmittedvia T antennas 234 a through 234 t, respectively. According to variousaspects described in more detail below, the synchronization signals canbe generated with location encoding to convey additional information.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. Each demodulator 254 may condition (e.g., filter, amplify,downconvert, and digitize) a received signal to obtain input samples.Each demodulator 254 may further process the input samples (e.g., forOFDM and/or the like) to obtain received symbols. A MIMO detector 256may obtain received symbols from all R demodulators 254 a through 254 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive processor 258 may process (e.g.,demodulate and decode) the detected symbols, provide decoded data for UE120 to a data sink 260, and provide decoded control information andsystem information to a controller/processor 280. A channel processormay determine reference signal received power (RSRP), received signalstrength indicator (RSSI), reference signal received quality (RSRQ),channel quality indicator (CQI), and/or the like.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) fromcontroller/processor 280. Transmit processor 264 may also generatereference symbols for one or more reference signals. The symbols fromtransmit processor 264 may be precoded by a TX MIMO processor 266 ifapplicable, further processed by modulators 254 a through 254 r (e.g.,for DFT-s-OFDM, CP-OFDM, and/or the like), and transmitted to basestation 110. At base station 110, the uplink signals from UE 120 andother UEs may be received by antennas 234, processed by demodulators232, detected by a MIMO detector 236 if applicable, and furtherprocessed by a receive processor 238 to obtain decoded data and controlinformation sent by UE 120. Receive processor 238 may provide thedecoded data to a data sink 239 and the decoded control information tocontroller/processor 240. Base station 110 may include communicationunit 244 and communicate to network controller 130 via communicationunit 244. Network controller 130 may include communication unit 294,controller/processor 290, and memory 292.

In some aspects, one or more components of UE 120 may be included in ahousing. Controller/processor 240 of base station 110,controller/processor 280 of UE 120, and/or any other component(s) ofFIG. 2 may perform one or more techniques associated with uplink controlchannel resource allocation determination, as described in more detailelsewhere herein. For example, controller/processor 240 of base station110, controller/processor 280 of UE 120, and/or any other component(s)of FIG. 2 may perform or direct operations of, for example, process 1000of FIG. 10, process 1100 of FIG. 11, and/or other processes as describedherein. Memories 242 and 282 may store data and program codes for basestation 110 and UE 120, respectively. A scheduler 246 may schedule UEsfor data transmission on the downlink and/or uplink.

In some aspects, UE 120 may include means for determining a resourceallocation, from a resource set, for a response message using a resourceallocation selection procedure based at least in part on at least one ofa downlink assignment characteristic (e.g., the number of DCI messages,whether there is cross-carrier or cross-slot scheduling, whether the DCIis received on PCC or SCC, how many ACK/NACK bits are needed for theresponse message, whether ARI has changed, etc.), a downlink assignmentindex (DAI) value, a resource set characteristic for the resource set, aquantity of acknowledgement bits in an acknowledgement message, or aresponse message resource indicator value; means for transmitting theresponse message using the resource allocation and based at least inpart on determining the resource allocation; and/or the like. In someaspects, such means may include one or more components of UE 120described in connection with FIG. 2.

In some aspects, UE 120 may include means for determining, using animplicit resource mapping procedure and before a radio resource controlconnection establishment, a resource allocation for a redundancy schemeresponse message based at least in part on a remaining minimum systeminformation (RMSI) value; means for transmitting the redundancy schemeresponse message using the resource allocation based at least in part ondetermining the resource allocation; and/or the like. In some aspects,such means may include one or more components of UE 120 described inconnection with FIG. 2.

As indicated above, FIG. 2 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 2.

FIG. 3A shows an example frame structure 300 for FDD in atelecommunications system (e.g., NR). The transmission timeline for eachof the downlink and uplink may be partitioned into units of radioframes. Each radio frame may have a predetermined duration and may bepartitions into a set of Z (Z≥1) subframes (e.g., with indices of 0through Z−1). Each subframe may include a set of slots (e.g., two slotsper subframe are shown in FIG. 3A). Each slot may include a set of Lsymbol periods. For example, each slot may include seven symbol periods(e.g., as shown in FIG. 3A), fifteen symbol periods, and/or the like. Ina case where the subframe includes two slots, the subframe may include2L symbol periods, where the 2L symbol periods in each subframe may beassigned indices of 0 through 2L−1. In some aspects, a scheduling unitfor the FDD may frame-based, subframe-based, slot-based, symbol-based,and/or the like.

While some techniques are described herein in connection with frames,subframes, slots, and/or the like, these techniques may equally apply toother types of wireless communication structures, which may be referredto using terms other than “frame,” “subframe,” “slot,” and/or the likein 5G NR. In some aspects, a wireless communication structure may referto a periodic time-bounded communication unit defined by a wirelesscommunication standard and/or protocol. Additionally, or alternatively,different configurations of wireless communication structures than thoseshown in FIG. 3A may be used.

In certain telecommunications (e.g., NR), a base station may transmitsynchronization signals. For example, a base station may transmit aprimary synchronization signal (PSS), a secondary synchronization signal(SSS), and/or the like, on the downlink for each cell supported by thebase station. The PSS and SSS may be used by UEs for cell search andacquisition. For example, the PSS may be used by UEs to determine symboltiming, and the SSS may be used by UEs to determine a physical cellidentifier, associated with the base station, and frame timing. The basestation may also transmit a physical broadcast channel (PBCH). The PBCHmay carry some system information, such as system information thatsupports initial access by UEs.

In some aspects, the base station may transmit the PSS, the SSS, and/orthe PBCH in accordance with a synchronization communication hierarchy(e.g., a synchronization signal (SS) hierarchy) including multiplesynchronization communications (e.g., SS blocks), as described below inconnection with FIG. 3B.

FIG. 3B is a block diagram conceptually illustrating an example SShierarchy, which is an example of a synchronization communicationhierarchy. As shown in FIG. 3B, the SS hierarchy may include an SS burstset, which may include a plurality of SS bursts (identified as SS burst0 through SS burst B−1, where B is a maximum number of repetitions ofthe SS burst that may be transmitted by the base station). As furthershown, each SS burst may include one or more SS blocks (identified as SSblock 0 through SS block (b_(max_SS-1)), where b_(max_SS-1) is a maximumnumber of SS blocks that can be carried by an SS burst). In someaspects, different SS blocks may be beam-formed differently. An SS burstset may be periodically transmitted by a wireless node, such as every Xmilliseconds, as shown in FIG. 3B. In some aspects, an SS burst set mayhave a fixed or dynamic length, shown as Y milliseconds in FIG. 3B.

The SS burst set shown in FIG. 3B is an example of a synchronizationcommunication set, and other synchronization communication sets may beused in connection with the techniques described herein. Furthermore,the SS block shown in FIG. 3B is an example of a synchronizationcommunication, and other synchronization communications may be used inconnection with the techniques described herein.

In some aspects, an SS block includes resources that carry the PSS, theSSS, the PBCH, and/or other synchronization signals (e.g., a tertiarysynchronization signal (TSS)) and/or synchronization channels. In someaspects, multiple SS blocks are included in an SS burst, and the PSS,the SSS, and/or the PBCH may be the same across each SS block of the SSburst. In some aspects, a single SS block may be included in an SSburst. In some aspects, the SS block may be at least four symbol periodsin length, where each symbol carries one or more of the PSS (e.g.,occupying one symbol), the SSS (e.g., occupying one symbol), and/or thePBCH (e.g., occupying two symbols).

In some aspects, the symbols of an SS block are consecutive, as shown inFIG. 3B. In some aspects, the symbols of an SS block arenon-consecutive. Similarly, in some aspects, one or more SS blocks ofthe SS burst may be transmitted in consecutive radio resources (e.g.,consecutive symbol periods) during one or more subframes. Additionally,or alternatively, one or more SS blocks of the SS burst may betransmitted in non-consecutive radio resources.

In some aspects, the SS bursts may have a burst period, whereby the SSblocks of the SS burst are transmitted by the base station according tothe burst period. In other words, the SS blocks may be repeated duringeach SS burst. In some aspects, the SS burst set may have a burst setperiodicity, whereby the SS bursts of the SS burst set are transmittedby the base station according to the fixed burst set periodicity. Inother words, the SS bursts may be repeated during each SS burst set.

The base station may transmit system information, such as systeminformation blocks (SIBs) on a physical downlink shared channel (PDSCH)in certain subframes. The base station may transmit controlinformation/data on a physical downlink control channel (PDCCH) in Csymbol periods of a subframe, where B may be configurable for eachsubframe. The base station may transmit traffic data and/or other dataon the PDSCH in the remaining symbol periods of each subframe.

As indicated above, FIGS. 3A and 3B are provided as examples. Otherexamples may differ from what is described with regard to FIGS. 3A and3B.

FIG. 4 shows an example subframe format 410 with a normal cyclic prefix.The available time frequency resources may be partitioned into resourceblocks. Each resource block may cover a set of subcarriers (e.g., 12subcarriers) in one slot and may include a number of resource elements.Each resource element may cover one subcarrier in one symbol period(e.g., in time) and may be used to send one modulation symbol, which maybe a real or complex value. In some aspects, subframe format 410 may beused for transmission of SS blocks that carry the PSS, the SSS, thePBCH, and/or the like, as described herein.

An interlace structure may be used for each of the downlink and uplinkfor FDD in certain telecommunications systems (e.g., NR). For example, Qinterlaces with indices of 0 through Q−1 may be defined, where Q may beequal to 4, 6, 8, 10, or some other value. Each interlace may includesubframes that are spaced apart by Q frames. In particular, interlace qmay include subframes q, q+Q, q+2Q, etc., where q∈{0, . . . , Q−1}.

A UE may be located within the coverage of multiple BSs. One of theseBSs may be selected to serve the UE. The serving BS may be selectedbased at least in part on various criteria such as received signalstrength, received signal quality, path loss, and/or the like. Receivedsignal quality may be quantified by a signal-to-noise-and-interferenceratio (SINR), or a reference signal received quality (RSRQ), or someother metric. The UE may operate in a dominant interference scenario inwhich the UE may observe high interference from one or more interferingBSs.

While aspects of the examples described herein may be associated with NRor 5G technologies, aspects of the present disclosure may be applicablewith other wireless communication systems. New Radio (NR) may refer toradios configured to operate according to a new air interface (e.g.,other than Orthogonal Frequency Divisional Multiple Access (OFDMA)-basedair interfaces) or fixed transport layer (e.g., other than InternetProtocol (IP)). In aspects, NR may utilize OFDM with a CP (hereinreferred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDM on theuplink, may utilize CP-OFDM on the downlink and include support forhalf-duplex operation using TDD. In aspects, NR may, for example,utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discreteFourier transform spread orthogonal frequency-division multiplexing(DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink andinclude support for half-duplex operation using TDD. NR may includeEnhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g.,80 megahertz (MHz) and beyond), millimeter wave (mmW) targeting highcarrier frequency (e.g., 60 gigahertz (GHz)), massive MTC (mMTC)targeting non-backward compatible MTC techniques, and/or missioncritical targeting ultra reliable low latency communications (URLLC)service.

In some aspects, a single component carrier bandwidth of 100 MHZ may besupported. NR resource blocks may span 12 sub-carriers with asub-carrier bandwidth of 60 or 120 kilohertz (kHz) over a 0.1millisecond (ms) duration. Each radio frame may include 40 subframeswith a length of 10 ms. Consequently, each subframe may have a length of0.25 ms. Each subframe may indicate a link direction (e.g., DL or UL)for data transmission and the link direction for each subframe may bedynamically switched. Each subframe may include DL/UL data as well asDL/UL control data.

Beamforming may be supported and beam direction may be dynamicallyconfigured. MIMO transmissions with precoding may also be supported.MIMO configurations in the DL may support up to 8 transmit antennas withmulti-layer DL transmissions up to 8 streams and up to 2 streams per UE.Multi-layer transmissions with up to 2 streams per UE may be supported.Aggregation of multiple cells may be supported with up to 8 servingcells. Alternatively, NR may support a different air interface, otherthan an OFDM-based interface. NR networks may include entities suchcentral units or distributed units.

As indicated above, FIG. 4 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 4.

FIG. 5 illustrates an example logical architecture of a distributed RAN500, according to aspects of the present disclosure. A 5G access node506 may include an access node controller (ANC) 502. The ANC may be acentral unit (CU) of the distributed RAN 500. The backhaul interface tothe next generation core network (NG-CN) 504 may terminate at the ANC.The backhaul interface to neighboring next generation access nodes(NG-ANs) may terminate at the ANC. The ANC may include one or more TRPs508 (which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs,gNB, or some other term). As described above, a TRP may be usedinterchangeably with “cell.”

The TRPs 508 may be a distributed unit (DU). The TRPs may be connectedto one ANC (ANC 502) or more than one ANC (not illustrated). Forexample, for RAN sharing, radio as a service (RaaS), and servicespecific AND deployments, the TRP may be connected to more than one ANC.A TRP may include one or more antenna ports. The TRPs may be configuredto individually (e.g., dynamic selection) or jointly (e.g., jointtransmission) serve traffic to a UE.

The local architecture of RAN 500 may be used to illustrate fronthauldefinition. The architecture may be defined to support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based at least in part on transmit networkcapabilities (e.g., bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 510 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 508. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 502. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture of RAN 500. The packet dataconvergence protocol (PDCP), radio link control (RLC), media accesscontrol (MAC) protocol may be adaptably placed at the ANC or TRP.

According to various aspects, a BS may include a central unit (CU)(e.g., ANC 502) and/or one or more distributed units (e.g., one or moreTRPs 508).

As indicated above, FIG. 5 is provided merely as an example. Otherexamples may differ from what was described with regard to FIG. 5.

FIG. 6 illustrates an example physical architecture of a distributed RAN600, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 602 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 604 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A distributed unit (DU) 606 may host one or more TRPs. The DU may belocated at edges of the network with radio frequency (RF) functionality.

As indicated above, FIG. 6 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 6.

FIG. 7 is a diagram 700 showing an example of a DL-centric subframe orwireless communication structure. The DL-centric subframe may include acontrol portion 702. The control portion 702 may exist in the initial orbeginning portion of the DL-centric subframe. The control portion 702may include various scheduling information and/or control informationcorresponding to various portions of the DL-centric subframe. In someconfigurations, the control portion 702 may be a physical DL controlchannel (PDCCH), as indicated in FIG. 7. In some aspects, the controlportion 702 may include legacy PDCCH information, shortened PDCCH(sPDCCH) information), a control format indicator (CFI) value (e.g.,carried on a physical control format indicator channel (PCFICH)), one ormore grants (e.g., downlink grants, uplink grants, and/or the like),and/or the like.

The DL-centric subframe may also include a DL data portion 704. The DLdata portion 704 may sometimes be referred to as the payload of theDL-centric subframe. The DL data portion 704 may include thecommunication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 704 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include an UL short burst portion 706.The UL short burst portion 706 may sometimes be referred to as an ULburst, an UL burst portion, a common UL burst, a short burst, an ULshort burst, a common UL short burst, a common UL short burst portion,and/or various other suitable terms. In some aspects, the UL short burstportion 706 may include one or more reference signals. Additionally, oralternatively, the UL short burst portion 706 may include feedbackinformation corresponding to various other portions of the DL-centricsubframe. For example, the UL short burst portion 706 may includefeedback information corresponding to the control portion 702 and/or thedata portion 704. Non-limiting examples of information that may beincluded in the UL short burst portion 706 include an ACK signal (e.g.,a PUCCH ACK, a PUSCH ACK, an immediate ACK), a NACK signal (e.g., aPUCCH NACK, a PUSCH NACK, an immediate NACK), a scheduling request (SR),a buffer status report (BSR), a HARQ indicator, a channel stateindication (CSI), a channel quality indicator (CQI), a soundingreference signal (SRS), a demodulation reference signal (DMRS), PUSCHdata, and/or various other suitable types of information. The UL shortburst portion 706 may include additional or alternative information,such as information pertaining to random access channel (RACH)procedures, scheduling requests, and various other suitable types ofinformation.

As illustrated in FIG. 7, the end of the DL data portion 704 may beseparated in time from the beginning of the UL short burst portion 706.This time separation may sometimes be referred to as a gap, a guardperiod, a guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the subordinate entity (e.g., UE)) to ULcommunication (e.g., transmission by the subordinate entity (e.g., UE)).The foregoing is merely one example of a DL-centric wirelesscommunication structure, and alternative structures having similarfeatures may exist without necessarily deviating from the aspectsdescribed herein.

As indicated above, FIG. 7 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 7.

FIG. 8 is a diagram 800 showing an example of an UL-centric subframe orwireless communication structure. The UL-centric subframe may include acontrol portion 802. The control portion 802 may exist in the initial orbeginning portion of the UL-centric subframe. The control portion 802 inFIG. 8 may be similar to the control portion 702 described above withreference to FIG. 7. The UL-centric subframe may also include an UL longburst portion 804. The UL long burst portion 804 may sometimes bereferred to as the payload of the UL-centric subframe. The UL portionmay refer to the communication resources utilized to communicate UL datafrom the subordinate entity (e.g., UE) to the scheduling entity (e.g.,UE or BS). In some configurations, the control portion 802 may be aphysical DL control channel (PDCCH).

As illustrated in FIG. 8, the end of the control portion 802 may beseparated in time from the beginning of the UL long burst portion 804.This time separation may sometimes be referred to as a gap, guardperiod, guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the scheduling entity) to UL communication(e.g., transmission by the scheduling entity).

The UL-centric subframe may also include an UL short burst portion 806.The UL short burst portion 806 in FIG. 8 may be similar to the UL shortburst portion 706 described above with reference to FIG. 7, and mayinclude any of the information described above in connection with FIG.7. The foregoing is merely one example of an UL-centric wirelesscommunication structure, and alternative structures having similarfeatures may exist without necessarily deviating from the aspectsdescribed herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some aspects, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

In one example, a wireless communication structure, such as a frame, mayinclude both UL-centric subframes and DL-centric subframes. In thisexample, the ratio of UL-centric subframes to DL-centric subframes in aframe may be dynamically adjusted based at least in part on the amountof UL data and the amount of DL data that are transmitted. For example,if there is more UL data, then the ratio of UL-centric subframes toDL-centric subframes may be increased. Conversely, if there is more DLdata, then the ratio of UL-centric subframes to DL-centric subframes maybe decreased.

As indicated above, FIG. 8 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 8.

A BS may allocate resources to a UE to enable the UE to transmitinformation to the BS. For example, the BS may transmit an indication,using a downlink channel, of a resource allocation of an uplink channelthat the UE is to utilize for communication. The UE may receive theindication of the resource allocation, and may determine the resourceallocation for transmitting a response message. For example, the UE mayuse the resource allocation for transmitting an acknowledgement message,a negative acknowledgement message, and/or the like. The UE may use aresource allocation selection procedure to map an indication of aresource allocation to the resource allocation.

In some cases, the UE may use an explicit or fixed mapping procedurewhere the resource allocation is statically determined from a resourceset. However, the fixed resource mapping procedure may result in the BSbeing unable to select which resources the UE uses of a group ofavailable resources in a resource set. Alternatively, the UE may use animplicit resource mapping procedure. However, use of the implicitresource mapping procedure may result in the UE failing to accuratelymap an indication of a resource allocation to the resource allocation insome cases. For example, during a cross-slot scheduling scenario with aplurality of downlink channels, during a carrier aggregation scenario,during an initial access scenario, and/or the like, the UE may fail toidentify a correct resource (e.g., a same resource that a BS hasallocated for the UE) in a resource set of a resource pool using animplicit resource mapping procedure.

Some aspects described herein may enable dynamic determination ofwhether to use an implicit resource mapping procedure to identify aresource allocation, and may enable identification and utilization ofthe resource allocation. For example, a UE may determine whether to usean implicit resource mapping procedure and/or may select from aplurality of implicit resource mapping procedures for use during across-slot scheduling scenario, a carrier aggregation scenario, aninitial access scenario, and/or the like. In this way, the UE improves alikelihood of correctly identifying a resource allocation for an uplinkcontrol channel and for use in transmitting a response message, therebyimproving network performance.

FIG. 9 is a diagram illustrating an example 900 of uplink controlchannel resource allocation determination, in accordance with variousaspects of the present disclosure. As shown in FIG. 9, example 900includes a BS 110 and a UE 120.

As further shown in FIG. 9, and by reference number 910, UE 120 mayreceive at least one downlink channel message. For example, UE 120 mayreceive a message associated with a PDCCH. In some aspects, UE 120 mayreceive a message associated with a PDSCH. In some aspects, UE 120 mayreceive a message for acknowledgement. For example, UE 120 may receive adownlink control information (DCI) message, and may determine toacknowledge the DCI message using a resource allocation of a PUCCH. Insome aspects, UE 120 may receive a radio resource control (RRC) message.For example, UE 120 may receive an RRC message associated with providingone or more parameters for UE 120 to use to determine the resourceallocation. In some aspects, UE 120 may receive a plurality of PDCCHs.For example, in a cross slot scheduling scenario, UE 120 may receive aplurality of PDCCHs associated with a plurality of slots.

Additionally, or alternatively, in a carrier aggregation scenario, UE120 may receive a plurality of PDCCHs associated with a plurality ofcomponent carriers (e.g., each of which may be associated with adifferent control channel element), a primary component carrier and asecondary component carrier, and/or the like. In some aspects, UE 120may receive at least one message associated with at least one PDCCH in across slot scheduling and carrier aggregation scenario.

In some aspects, UE 120 may determine to use the implicit resourcemapping procedure based at least in part on a quantity ofacknowledgement bits provided in an acknowledgement message. Forexample, UE 120 may determine to use the implicit resource mappingprocedure when the number of acknowledgement bits provided in anacknowledgement message is one or two. In some aspects, UE 120 maydetermine to use the implicit resource mapping procedure for a pluralityof PDCCHs. For example, UE 120 may determine to use the implicitresource mapping procedure when one or two PDCCHs are provided by BS110. In some aspects, UE 120 may use the implicit resource mappingprocedure combined with explicit signaling. For example, UE 120 mayreceive some explicit signaling (e.g., identifying a portion of mapping,including acknowledgement bits to indicate use of implicit resourcemapping, and/or the like), and may perform implicit resource mapping inconnection with the explicit signaling.

In some aspects, UE 120 may receive at least one message in an initialaccess scenario. For example, UE 120 may receive a message before an RRCconnection setup, and may transmit a redundancy scheme response messageto indicate successful receipt of the message. In this case, theredundancy scheme response message may be a hybrid automatic repeatrequest (HARD) acknowledgement (HARQ-ACK) or negative acknowledgement(HARQ-NACK) message. In some aspects, UE 120 may receive a messageidentifying a remaining system information (RMSI) value (e.g., a 4-bitparameter) associated with the HARQ-ACK message, and may determine aresource allocation for the HARQ-ACK based at least in part on the RMSIvalue.

As further shown in FIG. 9, and by reference number 920, UE 120 maydetermine a resource allocation based at least in part on a set ofparameters associated with the at least one downlink channel message. Insome aspects, UE 120 may determine a resource allocation selectionscheme to utilize to determine the resource allocation based at least inpart on the set of parameters.

In some aspects, the UE may determine the resource index based at leastin part on implicit mapping from the starting resource block (RB) of thedownlink data channel. For example, when the quantity of resources inthe resource set is 2, an even RB of the downlink data channel mayindicate to use the first resource, an odd RB of the downlink datachannel may indicate to use the second resource, and/or the like. Inthis case, UE 120 may determine the resource allocation based at leastin part on an equation r=mod(N, M), where r is the determined resourceindex, N is the starting RB index of the PDSCH, and M is a quantity ofPUCCH resources in a subset of PUCCH resources (e.g., of a resourcepool) identified based at least in part on the ARI bits.

In some aspects, the UE may determine the resource allocation using theimplicit resource mapping procedure based at least in part on a startingresource block (RB) index or a starting RB group (RBG) index of thedownlink data channel. For example, when the quantity of resources inthe resource set is 2, an even RB index or RBG index of the downlinkdata channel may indicate use of a first resource, an odd RB index orRBG index of the downlink data channel may indicate use of the secondresource, and/or the like. In this case, UE 120 may determine theresource allocation based at least in part on an equation r=mod(N, M),where r is the determined resource index, N is the starting RB index ofa downlink data channel, and M is a quantity of PUCCH resources in asubset of PUCCH resources (e.g., of a resource pool) identified based atleast in part on the ARI bits. In some aspects, the resource pool maychange when a quantity of ACK bits or NACK bits satisfies a thresholdcorresponding to a format of the PUCCH.

In some aspects, UE 120 may determine the resource allocation based atleast in part on an equation r=mod(N/G, M), where G is the quantity ofRBs in an RBG, and N/G represents a starting RBG index of the downlinkdata channel. In some aspects, a starting RB index and a correspondingstarting RBG index may be defined in a UE specific UL bandwidth part(BWP). For example, the starting RB index or the starting RBG index maybe UE-specific values and may not be unique for the same physical RBs(PRB). In some aspects, the starting RB index and the correspondingstarting RBG index may be defined for a system bandwidth. For example,the starting RB index or the starting RBG index may be cell-specific andunique for the same PRB.

In some aspects, such as in a cross-slot scheduling scenario, a carrieraggregation scenario, and/or the like, the BS may assign the multipledownlink data channels across slots and across component carriers (CCs)with starting RB indices or starting RBG indices that will be mapped tothe same resource index in the resource set. For example, when M=2 thereis only two resources in the resource set. The BS may use an evenstarting RB index or starting RBG index to transmit a plurality ofdownlink data channels when the response messages for the downlink datachannels are transmitted at the same UL resource. In this case, the UEwill use the first UL resource, such as when some of the plurality ofdownlink control channels are not decoded successfully. Additionally, oralternatively, the BS may use an odd starting RB index or RBG index totransmit the plurality of downlink data channels, such as when responsemessages for the plurality of downlink data channels are transmittedusing the same UL resource. In this case, the UE may use another ULresource, such as when some of the plurality of downlink controlchannels are not decoded successfully.

In some aspects, a UE may determine the resource index by implicitmapping based at least in part on one of the downlink control channelcharacteristic. For example, in a cross slot scheduling scenario, UE 120may determine a downlink channel characteristic (e.g., a downlinkcontrol channel characteristic, a downlink data channel characteristic,and/or the like), such as that a single PDCCH is detected, and maydetermine to use an implicit resource mapping procedure based at leastin part on the single PDCCH being detected.

Additionally, or alternatively, UE 120 may determine to use the implicitresource mapping procedure based at least in part on determining that avalue for a downlink assignment index (DAI) is zero and a quantity ofdecoded PDCCHs corresponding to a PUCCH is one. In this case, UE 120 maydetermine that BS 110 provided a single PDCCH, and may use the implicitresource mapping procedure to select a resource allocation. In someaspects, such as in a carrier aggregation scenario, UE 120 may determineto use the implicit resource mapping procedure when a single PDDCH isdetected on a primary component carrier. Additionally, or alternatively,UE 120 may determine to use the implicit resource mapping procedure whena DAI value has increased by one relative to a previous DAI value. Inthis case, UE 120 may determine, based at least in part on the DAIvalues, that a single component carrier is used, and may use theimplicit resource mapping procedure.

Additionally, or alternatively, UE 120 may determine to use the implicitresource mapping procedure based at least in part on a resource setcharacteristic. For example, based at least in part on a last receivedPDCCH being associated with a different resource pool from one or moreother PDCCHs, UE 120 may determine to use the implicit resource mappingprocedure. Additionally, or alternatively, UE 120 may determine to usethe implicit resource mapping procedure based at least in part on aresponse message resource indicator value. For example, based at leastin part on determining that an acknowledgement/negative-acknowledgement(A/N) resource indicator (ARI) value has changed relative to a previousARI value associated with a previous PDCCH, UE 120 may determine to usethe implicit resource mapping procedure.

In some aspects, UE 120 may determine to use a fixed resource mappingprocedure. For example, based at least in part on detecting a pluralityof PDCCHs, UE 120 may use the fixed resource mapping procedure.Additionally, or alternatively, UE 120 may determine to use the fixedresource mapping procedure based at least in part on a DAI value notbeing zero or a quantity of decoded PDCCHs corresponding to a PUCCHbeing greater than one. Additionally, or alternatively, UE 120 maydetermine to use the fixed resource mapping procedure based at least inpart on a resource pool associated with a last received PDCCH notchanging and an ARI value not changing.

In some aspects, UE 120 may determine the resource allocation using afixed resource allocation procedure. For example, UE 120 may determineto use a first identified resource of a set of resources of a resourcepool. In some aspects, UE 120 may determine the resource allocationusing a selected implicit resource mapping procedure of a plurality ofimplicit resource mapping procedures. For example, UE 120 may determineto use a control channel element (CCE) based implicit resource mappingprocedure for determining a resource allocation. In some case, UE 120may determine the resource allocation based at least in part on anequation r=mod(C/L, M), where r is the determined resource allocation, Cis a starting CCE index, L is an aggregation level of a last receivedPDCCH that includes ARI bits, and M is a quantity of PUCCH resources ina subset of PUCCH resources (e.g., of a resource pool) identified basedat least in part on the ARI bits. In some case, UE 120 may determine theresource allocation based at least in part on an equation r=mod(C, M).In some case, UE 120 may determine the resource allocation based atleast in part on one of the equations r=mod(C/L, M) or r=mod(C, M)according to the value of M. For example, when M is not power of 2, theUE will use r=mod(C, M). When M is power of 2, the UE will user=mod(C/L, M). In another example, the UE may determine to use r=mod(C,M) when M is power of 2 but L<M and to use r=mod(C*M/L/2, M) when M ispower of 2 and L is greater than or equal to M.

Additionally, or alternatively, UE 120 may select a DAI based implicitresource mapping procedure. For example, UE 120 may determine theresource allocation based at least in part on an equation r=mod(D, M),where D is a total DAI value for a last received PDCCH. In this way, BS110 may pseudo-randomize resource allocation based at least in part ondiffering values for the DAI for different PDCCHs. Additionally, oralternatively, UE 120 may select a redundancy check based implicitresource mapping procedure. For example, UE 120 may determine theresource allocation based at least in part on a cyclic redundancy check(CRC) mask value. In this way, BS 110 may control the resourceallocation by controlling the value for the CRC mask, and may maintain acommon CRC mask across multiple PDCCHs to ensure consistent resourceallocation selection.

In some aspects, UE 120 may determine to select the CCE based implicitresource mapping procedure. For example, UE 120 may select the CCE basedimplicit resource mapping procedure when a DAI value is 0. Additionally,or alternatively, UE 120 may select the CCE based implicit resourcemapping procedure when a single component carrier is used (e.g.,determined based at least in part on a DAI value change relative to aprevious DAI value), when a resource pool changes, when ARI bits changefor an unchanged resource pool, and/or the like. Alternatively, UE 120may select the DAI based implicit resource mapping procedure or the CRCbased implicit resource mapping procedure when one or more of theseconditions are satisfied.

In some aspects, UE 120 may determine the resource allocation for aninitial access acknowledgement message. For example, when UE 120 is totransmit a HARQ-ACK before an RRC connection setup, UE 120 may determinethe resource allocation using the implicit resource mapping procedure.In this case, UE 120 may identify a PUCCH resource from a set ofresources based at least in part on an RMSI value. In some aspects, UE120 may determine the set of resources using a resource allocationindex. For example, UE 120 may store a table or another type of datastructure, and may select a table value based at least in part on theRMSI value. In this case, the table value may correspond to a resourceset of a resource pool. In some aspects, UE 120 may select the set ofresources based at least in part on a resource block offset value. Forexample, UE 120 may store a table or another type of data structureidentifying each candidate resource set of a plurality of resource sets,and may use the resource block index value and a resource block offsetvalue corresponding to the RMSI value to select a particular resourceset from the candidate resource sets. In some aspects, UE 120 maydetermine the resource allocation for an initial access acknowledgementmessage by implicit mapping from the starting CCE index of the downlinkcontrol for message 4. In some case the number of resources, M, in theresource set is greater than the maximum aggregation level L_max. Inthis, the UE may determine the resource allocation using the equationr=mod(C, M).

As further shown in FIG. 9, and by reference number 930, UE 120 maytransmit at least one uplink channel response message using allocatedresources based at least in part on determining the resource allocation.For example, UE 120 may transmit an acknowledgement message, a negativeacknowledgement message, a HARQ-ACK, a HARQ-NACK, and/or the like usinga resource allocation of a PUCCH and/or the like.

As indicated above, FIG. 9 is provided as an example. Other examples arepossible and may differ from what was described with respect to FIG. 9.

FIG. 10 is a diagram illustrating an example process 1000 performed, forexample, by a UE, in accordance with various aspects of the presentdisclosure. Example process 1000 is an example where a UE (e.g., UE 120)performs uplink control channel resource allocation determination.

As shown in FIG. 10, in some aspects, process 1000 may includedetermining a resource allocation, from a resource set, for a responsemessage using a resource allocation selection procedure based at leastin part on at least one of a downlink assignment characteristic, adownlink assignment index (DAI) value, a resource set characteristic forthe resource set, a quantity of acknowledgement bits in anacknowledgement message, or a response message resource indicator value(block 1010). For example, the UE may determine (e.g., using receiveprocessor 258, transmit processor 264, controller/processor 280, and/orthe like) the resource allocation for the response message based atleast in part on a downlink control channel characteristic, a downlinkdata channel characteristic, the DAI value, the resource setcharacteristic, the response message resource indicator value, and/orthe like, as described in more detail above. In some aspects, theresource allocation selection procedure comprises an implicit resourcemapping procedure combined with explicit signaling. For example,implicit mapping may be performed based at least in part on a controlchannel element (CCE) index, and explicit signaling may be provided(e.g., via a physical uplink control channel (PUCCH) indicator). In someaspects, the UE may determine the resource allocation for the responsemessage based at least in part on the downlink data channelcharacteristic (e.g., the starting RB of the PDSCH channel).

As shown in FIG. 10, in some aspects, process 1000 may includetransmitting the response message using the resource allocation andbased at least in part on determining the resource allocation (block1020). For example, the UE may transmit (e.g., using transmit processor264, TX MIMO processor 266, modulator 254, antenna 252, and/or the like)the response message using the resource allocation, as described in moredetail above.

Process 1000 may include additional aspects, such as any single aspectand/or any combination of aspects described below and/or in connectionwith one or more other processes described elsewhere herein.

In some aspects, the implicit resource mapping procedure is used todetermine the resource allocation and the implicit resource mappingprocedure is selected based at least in part on the at least one of thedownlink control channel characteristic, the DAI value, the resource setcharacteristic for the resource set, a quantity of acknowledgement bitsin an acknowledgement message, or the response message resourceindicator value. In some aspects, the resource set is a subset of aresource pool and is identified based at least in part on the responsemessage resource indicator value. In some aspects, the resourceallocation is determined, using the implicit resource mapping procedure,based at least in part on at least one of a quantity of resources in theresource set, a control channel element index associated with a downlinkcontrol channel, or an aggregation level associated with the downlinkcontrol channel.

In some aspects, the fixed resource mapping procedure is used todetermine the resource allocation based at least in part on the at leastone of the downlink control channel characteristic, the DAI value, theresource set characteristic for the resource set, a quantity ofacknowledgement bits in an acknowledgement message, or the responsemessage resource indicator value. In some aspects, the resourceallocation is determined, using the fixed resource mapping procedure, ona preconfigured resource selection rule. In some aspects, the implicitresource mapping procedure is selected based at least in part on atleast one of the downlink assignment characteristic, the DAI valueindicating a single downlink channel, or on a downlink data channelcharacteristic.

In some aspects, the implicit resource mapping procedure is selectedbased at least in part on the resource set characteristic indicating analteration to the resource set. In some aspects, the implicit resourcemapping procedure is selected based at least in part on an alteration tothe response message resource indicator value and the resource setcharacteristic indicating no alteration to the resource set. In someaspects, the fixed resource mapping procedure is selected based at leastin part on at least one of at least one of the downlink control channelcharacteristic or the DAI value indicating a plurality of downlinkcontrol channels, or the resource set characteristic indicating noalteration to the resource set and determining no alteration to theresponse message resource indicator value.

In some aspects, the implicit resource mapping procedure is selectedbased at least in part on at least one of the downlink control channelcharacteristic or the DAI value indicating a single downlink controlchannel for a primary component carrier. In some aspects, the implicitresource mapping procedure is selected based at least in part on the DAIvalue and a previous DAI value indicating a single component carrier. Insome aspects, the resource allocation is determined, using the implicitresource mapping procedure, based at least in part on at least one ofthe DAI value or a redundancy check mask value.

In some aspects, the UE may determine the resource allocation for theresponse message based at least in part on the downlink data channelcharacteristic (e.g., the starting RB of the PDSCH channel).

In some aspects, the implicit resource mapping procedure is selectedfrom a plurality of implicit resource mapping procedures. In someaspects, the resource allocation is determined, using the implicitresource mapping procedure, based at least in part on a control channelelement index and based at least in part on determining at least one ofa single downlink control channel, a single component carrier, a changeto the resource set, a quantity of acknowledgement bits in anacknowledgement message, or a change to the response message resourceindicator value. In some aspects, the resource allocation is determined,using the implicit resource mapping procedure, based at least in part onthe DAI value and based at least in part on determining at least one ofa plurality of downlink control channels, a plurality of componentcarriers, no change to the resource set and no change to the responsemessage resource indicator value, and/or the like.

In some aspects, the response message is an acknowledgement message or anegative-acknowledgement message. In some aspects, the resourceallocation is a physical uplink control channel resource allocation. Insome aspects, a downlink channel relating to the downlink assignmentcharacteristic is a physical downlink channel. In some aspects, adownlink data channel relating to the downlink assignment characteristicis a physical downlink data channel (e.g., a PDSCH). In some aspects,the response message resource indicator value is an acknowledgementnegative-acknowledgement (A/N) resource indicator (ARI) value.

In some aspects, the UE is operating in a carrier aggregation scenario,the downlink assignment characteristic indicates that a single grant isassociated with a primary component carrier, and the resource allocationselection procedure is the implicit resource mapping procedure. In someaspects, the UE is configured for carrier aggregation operation, and thedownlink assignment characteristic indicates a plurality of decodedgrants, and the resource allocation selection procedure is the fixedresource mapping procedure. In some aspects, the UE is operating in acarrier aggregation scenario, the downlink assignment characteristicindicates a grant decoded in connection with a secondary componentcarrier, and the resource allocation selection procedure is the fixedresource mapping procedure.

In some aspects, the UE is configured for carrier aggregation operationand cross slot scheduling, and the downlink assignment characteristicindicates a plurality of downlink channels, each grant, of a pluralityof grants, is associated with a common component carrier, and theresource allocation selection procedure is the implicit resource mappingprocedure. In some aspects, the UE is configured for carrier aggregationoperation and cross slot scheduling, and the downlink assignmentcharacteristic indicates a plurality of downlink channels, the resourceset characteristic indicates a change to the resource set, and theresource allocation selection procedure is the implicit resource mappingprocedure. In some aspects, the resource allocation is determined, usingthe implicit resource mapping procedure, based at least in part on atleast one of a resource block index or a resource block group indexassociated with a downlink channel, and the downlink channel is adownlink data channel. In some aspects, the UE is operating in a carrieraggregation and cross slot scheduling scenario, the downlink assignmentcharacteristic indicates a plurality of downlink channels, the responsemessage resource indicator value indicates a change relative to aprevious response message resource indicator value, and the resourceallocation selection procedure is the implicit resource mappingprocedure. In some aspects, the UE is configured to determine to use theimplicit resource mapping procedure based at least in part on a quantityof acknowledgement bits in an acknowledgement message. For example, theUE is configured to determine to use the implicit resource mappingprocedure when the number of acknowledgement bits is one or two.

Although FIG. 10 shows example blocks of process 1000, in some aspects,process 1000 may include additional blocks, fewer blocks, differentblocks, or differently arranged blocks than those depicted in FIG. 10.Additionally, or alternatively, two or more of the blocks of process1000 may be performed in parallel.

FIG. 11 is a diagram illustrating an example process 1100 performed, forexample, by a UE, in accordance with various aspects of the presentdisclosure. Example process 1100 is an example where a UE (e.g., UE 120)performs uplink control channel resource allocation determination.

As shown in FIG. 11, in some aspects, process 1100 may includedetermining, using an implicit resource mapping procedure and before aradio resource control connection establishment, a resource allocationfor a redundancy scheme response message based at least in part on aremaining minimum system information (RMSI) value (block 1110). Forexample, the UE may determine (e.g., using receive processor 258,transmit processor 264, controller/processor 280, and/or the like) theresource allocation for the redundancy scheme message based at least inpart on the RMSI value, as described in more detail above.

As shown in FIG. 11, in some aspects, process 1100 may includetransmitting the redundancy scheme response message using the resourceallocation based at least in part on determining the resource allocation(block 1120). For example, the UE may transmit (e.g., using transmitprocessor 264, TX MIMO processor 266, modulator 254, antenna 252, and/orthe like) the redundancy scheme response message using the resourceallocation, as described in more detail above.

Process 1100 may include additional aspects, such as any single aspectand/or any combination of aspects described below and/or in connectionwith one or more other processes described elsewhere herein.

In some aspects, a redundancy scheme associated with the redundancyscheme response message is hybrid automatic repeat request (HARQ) andthe response message is a HARQ acknowledgement (HARQ-ACK). In someaspects, the resource allocation is determined based at least in part ona resource allocation index, of a plurality of resource allocationindices associated with a corresponding plurality of resourceallocations that includes the resource allocation, identified based atleast in part on the RMSI value. In some aspects, the resourceallocation is determined based at least in part on a resource blockoffset identified based at least in part on the RMSI value. In someaspects, the resource allocation is determined based at least in part onat least one of resource block offset identified based at least in parton the RMSI value or a resource block group offset identified based atleast in part on the RMSI value.

Although FIG. 11 shows example blocks of process 1100, in some aspects,process 1100 may include additional blocks, fewer blocks, differentblocks, or differently arranged blocks than those depicted in FIG. 11.Additionally, or alternatively, two or more of the blocks of process1100 may be performed in parallel.

The foregoing disclosure provides illustration and description, but isnot intended to be exhaustive or to limit the aspects to the preciseform disclosed. Modifications and variations may be made in light of theabove disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construedas hardware, firmware, or a combination of hardware and software. Asused herein, a “processor” is implemented in hardware, firmware, and/ora combination of hardware and software.

It will be apparent that systems and/or methods, described herein, maybe implemented in different forms of hardware, firmware, and/or acombination of hardware and software. The actual specialized controlhardware or software code used to implement these systems and/or methodsis not limiting of the aspects. Thus, the operation and behavior of thesystems and/or methods were described herein without reference tospecific software code—it being understood that software and hardwarecan be designed to implement the systems and/or methods based, at leastin part, on the description herein.

Even though particular combinations of features are recited in theclaims and/or disclosed in the specification, these combinations are notintended to limit the disclosure of possible aspects. In fact, many ofthese features may be combined in ways not specifically recited in theclaims and/or disclosed in the specification. Although each dependentclaim listed below may directly depend on only one claim, the disclosureof possible aspects includes each dependent claim in combination withevery other claim in the claim set. A phrase referring to “at least oneof” a list of items refers to any combination of those items, includingsingle members. As an example, “at least one of: a, b, or c” is intendedto cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combinationwith multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c,a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering ofa, b, and c).

No element, act, or instruction used herein should be construed ascritical or essential unless explicitly described as such. Also, as usedherein, the articles “a” and “an” are intended to include one or moreitems, and may be used interchangeably with “one or more.” Furthermore,as used herein, the terms “set” and “group” are intended to include oneor more items (e.g., related items, unrelated items, a combination ofrelated and unrelated items, and/or the like), and may be usedinterchangeably with “one or more.” Where only one item is intended, theterm “only one” or similar language is used. Also, as used herein, theterms “has,” “have,” “having,” and/or the like are intended to beopen-ended terms. Further, the phrase “based on” is intended to mean“based, at least in part, on” unless explicitly stated otherwise.

What is claimed is:
 1. A method of wireless communication performed by auser equipment (UE), comprising: determining a resource allocation, froma resource set, for a response message using a resource allocationselection procedure based at least in part on a redundancy check maskvalue, wherein the resource allocation selection procedure comprises animplicit resource mapping procedure combined with an explicit signaling,wherein the explicit signaling identifies at least a portion of theresource set and includes a quantity of one or two acknowledgement bits,wherein the quantity of one or two acknowledgment bits indicates use ofthe implicit resource mapping procedure, wherein the implicit resourcemapping procedure uses different redundancy check mask values fordifferent resource allocations within the resource set, and wherein theredundancy check mask value is selected by a base station based on theresource allocation; and transmitting the response message using theresource allocation and based at least in part on determining theresource allocation.
 2. The method of claim 1, wherein the implicitresource mapping procedure is based at least in part on at least one ofa downlink assignment characteristic, a downlink assignment index (DAI)value, a resource set characteristic for the resource set, or a responsemessage resource indicator value.
 3. The method of claim 1, wherein theresource set is a subset of a resource pool and is identified based atleast in part on a response message resource indicator value.
 4. Themethod of claim 1, wherein the resource allocation is determined, usingthe implicit resource mapping procedure, based at least in part on atleast one of a quantity of resources in the resource set, a controlchannel element index associated with a downlink assignment on adownlink channel, or an aggregation level associated with the downlinkchannel.
 5. The method of claim 1, wherein the resource allocation isdetermined using a preconfigured resource selection rule.
 6. The methodof claim 1, wherein the implicit resource mapping procedure is based atleast in part on at least one of a downlink assignment characteristic ora downlink assignment index (DAI) value indicating that the responsemessage is associated with a single downlink assignment.
 7. The methodof claim 1, wherein the implicit resource mapping procedure is based atleast in part on detecting a change in a resource indicator value withina plurality of received downlink control information (DCI) messages. 8.The method of claim 1, wherein the implicit resource mapping procedureis based at least in part on detecting a change in a resource setassociated with a quantity of acknowledgement (ACK) bits to be sent inthe response message.
 9. The method of claim 1, wherein the implicitresource mapping procedure is based at least in part on at least one ofa downlink assignment characteristic or a downlink assignment index(DAI) value indicating a single downlink assignment on a primarycomponent carrier.
 10. The method of claim 1, wherein the implicitresource mapping procedure is based at least in part on a downlinkassignment index (DAI) value and a previous DAI value indicating asingle component carrier.
 11. The method of claim 1, wherein theimplicit resource mapping procedure is selected from a plurality ofimplicit resource mapping procedures.
 12. The method of claim 1, whereinthe resource allocation is determined, using the implicit resourcemapping procedure, based at least in part on a control channel elementindex and based at least in part on decoding a single downlinkassignment, a downlink assignment index (DAI) value and a previous DAIvalue indicating a single component carrier, detecting a change to theresource set, or detecting a change to a response message resourceindicator value in a plurality of decoded downlink control information(DCI) messages.
 13. The method of claim 1, wherein the resourceallocation is determined, using the implicit resource mapping procedure,based at least in part on a downlink assignment index (DAI) value andbased at least in part on at least one of: detecting a plurality ofdownlink assignments, detecting a plurality of component carriers onwhich the plurality of downlink assignments is received, or determiningno change to the resource set and no change to a response messageresource indicator value in the plurality of downlink assignmentsreceived.
 14. The method of claim 1, wherein the response message is anacknowledgement message or a negative-acknowledgement message.
 15. Themethod of claim 1, wherein the resource allocation is a physical uplinkcontrol channel resource allocation.
 16. The method of claim 1, whereinthe resource allocation is determined based at least in part on adownlink assignment characteristic associated with a physical downlinkcontrol channel.
 17. The method of claim 1, wherein the resourceallocation is determined based at least in part on anacknowledgement/negative-acknowledgement (A/N) resource indicator (ARI)value.
 18. The method of claim 1, wherein the UE is configured forcarrier aggregation operation and the resource allocation is determinedbased at least in part on a downlink assignment characteristic, andwherein the downlink assignment characteristic indicates a singleassignment is detected on a primary component carrier, and the resourceallocation selection procedure is the implicit resource mappingprocedure.
 19. The method of claim 1, wherein the UE is configured forcarrier aggregation operation with cross slot scheduling and theresource allocation is determined based at least in part on a downlinkassignment characteristic, and wherein the downlink assignmentcharacteristic indicates a plurality of downlink assignments arereceived, each assignment, of the plurality of assignments, isassociated with a common component carrier, and the resource allocationselection procedure is the implicit resource mapping procedure.
 20. Themethod of claim 1, wherein the UE is configured for carrier aggregationoperation and cross slot scheduling and the resource allocation isdetermined based at least in part on a downlink assignmentcharacteristic, and wherein the downlink assignment characteristicindicates a plurality of downlink assignments are received, the resourceset characteristic indicates a change to the resource set, and theresource allocation selection procedure is the implicit resource mappingprocedure.
 21. The method of claim 1, wherein the UE is configured forcarrier aggregation operation with cross slot scheduling and theresource allocation is determined based at least in part on a downlinkassignment characteristic and a response message resource indicator, andwherein the downlink assignment characteristic indicates a plurality ofdownlink assignments are received, the response message resourceindicator value indicates a change relative to a previous responsemessage resource indicator value, and the resource allocation selectionprocedure is the implicit resource mapping procedure.
 22. The method ofclaim 1, wherein the resource allocation is determined, using theimplicit resource mapping procedure, based at least in part on at leastone of a resource block index or a resource block group index associatedwith a downlink channel, and wherein the downlink channel is a downlinkdata channel.
 23. The method of claim 1, wherein a common cyclicredundancy check (CRC) is maintained across multiple physical downlinkcontrol channels (PDCCHs) for consistent resource allocation selection.24. The method of claim 1, wherein, when the UE is operating in acarrier aggregation scenario, the UE is configured to determine to usethe implicit resource mapping procedure based at least in part on adownlink assignment index (DAI) value being zero and a quantity ofdecoded physical downlink control channels (PDCCHs) being one.
 25. Auser equipment (UE) for wireless communication, comprising: a memory;and one or more processors coupled to the memory, the memory and the oneor more processors configured to: determine a resource allocation, froma resource set, for a response message using a resource allocationselection procedure based at least in part on a redundancy check maskvalue, wherein the resource allocation selection procedure comprises animplicit resource mapping procedure combined with an explicit signaling,wherein the explicit signaling identifies at least a portion of theresource set and includes a quantity of one or two acknowledgement bits,wherein the quantity of one or two acknowledgment bits indicates use ofthe implicit resource mapping procedure, wherein the implicit resourcemapping procedure uses different redundancy check mask values fordifferent resource allocations within the resource set, and wherein theredundancy check mask value is selected by a base station based on theresource allocation; and transmit the response message using theresource allocation and based at least in part on determining theresource allocation.
 26. The UE of claim 25, wherein the implicitresource mapping procedure is based at least in part on at least one ofa downlink assignment characteristic, a downlink assignment index (DAI)value, a resource set characteristic for the resource set, or a responsemessage resource indicator value.
 27. The UE of claim 25, wherein theresource set is a subset of a resource pool and is identified based atleast in part on a response message resource indicator value.
 28. The UEof claim 25, wherein the resource allocation is determined, using theimplicit resource mapping procedure, based at least in part on at leastone of a quantity of resources in the resource set, a control channelelement index associated with a downlink assignment on a downlinkchannel, or an aggregation level associated with the downlink channel.29. The UE of claim 25, wherein the resource allocation is determinedusing a preconfigured resource selection rule.
 30. The UE of claim 25,wherein the implicit resource mapping procedure is based at least inpart on at least one of a downlink assignment characteristic or adownlink assignment index (DAI) value indicating that the responsemessage is associated with a single downlink assignment.
 31. The UE ofclaim 25, wherein a common cyclic redundancy check (CRC) is maintainedacross multiple physical downlink control channels (PDCCHs) forconsistent resource allocation selection.
 32. The UE of claim 25,wherein, when the UE is operating in a carrier aggregation scenario, theUE is configured to determine to use the implicit resource mappingprocedure based at least in part on a downlink assignment index (DAI)value being zero and a quantity of decoded physical downlink controlchannels (PDCCHs) being one.
 33. A non-transitory computer-readablemedium storing instructions for wireless communication that whenexecuted by one or more processors of a user equipment (UE), cause theUE to: determine a resource allocation, from a resource set, for aresponse message using a resource allocation selection procedure basedat least in part on a redundancy check mask value, wherein the resourceallocation selection procedure comprises an implicit resource mappingprocedure combined with an explicit signaling, wherein the explicitsignaling identifies at least a portion of the resource set and includesa quantity of one or two acknowledgement bits, wherein the quantity ofone or two acknowledgment bits indicates use of the implicit resourcemapping procedure, wherein the implicit resource mapping procedure usesdifferent redundancy check mask values for different resourceallocations within the resource set, and wherein the redundancy checkmask value is selected by a base station based on the resourceallocation; and transmit the response message using the resourceallocation and based at least in part on determining the resourceallocation.
 34. The non-transitory computer-readable medium of claim 33,wherein the implicit resource mapping procedure is based at least inpart on at least one of a downlink assignment characteristic, a downlinkassignment index (DAI) value, a resource set characteristic for theresource set, or a response message resource indicator value.
 35. Thenon-transitory computer-readable medium of claim 33, wherein theresource set is a subset of a resource pool and is identified based atleast in part on a response message resource indicator value.
 36. Thenon-transitory computer-readable medium of claim 33, wherein a commoncyclic redundancy check (CRC) is maintained across multiple physicaldownlink control channels (PDCCHs) for consistent resource allocationselection.
 37. An apparatus for wireless communication, comprising:means for determining a resource allocation, from a resource set, for aresponse message using a resource allocation selection procedure basedat least in part on a redundancy check mask value, wherein the resourceallocation selection procedure comprises an implicit resource mappingprocedure combined with an explicit signaling, wherein the explicitsignaling identifies at least a portion of the resource set and includesa quantity of one or two acknowledgement bits, wherein the quantity ofone or two acknowledgment bits indicates use of the implicit resourcemapping procedure, wherein the implicit resource mapping procedure usesdifferent redundancy check mask values for different resourceallocations within the resource set, and wherein the redundancy checkmask value is selected by a base station based on the resourceallocation; and means for transmitting the response message using theresource allocation and based at least in part on determining theresource allocation.
 38. The apparatus of claim 37, wherein the implicitresource mapping procedure is based at least in part on at least one ofa downlink assignment characteristic, a downlink assignment index (DAI)value, a resource set characteristic for the resource set, or a responsemessage resource indicator value.
 39. The apparatus of claim 37, whereina common cyclic redundancy check (CRC) is maintained across multiplephysical downlink control channels (PDCCHs) for consistent resourceallocation selection.